I have two award bookings with AA, both have BA segments. One displays fine on BA MMB, and I chose my Z seats with no issues.

The other however, displays a message "our systems are not responding". This booking has an Amadeus PNR I haven't seen before - "5xxxxx" - but it displays fine on checkmytrip.com.

The second booking only has one BA segment - in U - thus I believe no seat selection with no status. Is this the reason it won't display at all?